瑞典隆德大学Sissel Sjöberg揭示了夜间鸣鸟迁徙过程中昼夜飞行的极端海拔。2021年5月7日国际知名学术期刊《科学》杂志发表了这一成果。

他们使用多传感器数据记录仪显示，当雄伟的芦苇莺（Acrocephalus arundinaceus）越过地中海和撒哈拉沙漠时，通常会将其夜间活动严格地延长到白天。出乎意料的是，延长飞行时间时，它们在黎明时急剧爬升，从白天的平均海拔2394米上升到极端的巡航高度（平均5367米，最高海拔6267米）。

白天在迁移时使用极高的飞行高度的这种先前未知的行为可能是由环境温度、风、掠食、视距和太阳辐射的变化引起的。他们对这一显著行为的发现为鸟类飞行的限制提供了新的视角，并可能有助于解释夜间迁徙的演变。

据悉，数十亿只夜行性鸣鸟在每年都会飞越海洋和沙漠而迁徙。

附：英文原文

Title: Extreme altitudes during diurnal flights in a nocturnal songbird migrant

Author: Sissel Sjberg, Gintaras Malmiga, Andreas Nord, Arne Andersson, Johan Bckman, Maja Tarka, Mikkel Willemoes, Kasper Thorup, Bengt Hansson, Thomas Alerstam, Dennis Hasselquist

Issue&Volume: 2021/05/07

Abstract: Billions of nocturnally migrating songbirds fly across oceans and deserts on their annual journeys. Using multisensor data loggers, we show that great reed warblers (Acrocephalus arundinaceus) regularly prolong their otherwise strictly nocturnal flights into daytime when crossing the Mediterranean Sea and the Sahara Desert. Unexpectedly, when prolonging their flights, they climbed steeply at dawn, from a mean of 2394 meters above sea level to reach extreme cruising altitudes (mean 5367 and maximum 6267 meters above sea level) during daytime flights. This previously unknown behavior of using exceedingly high flight altitudes when migrating during daytime could be caused by diel variation in ambient temperature, winds, predation, vision range, and solar radiation. Our finding of this notable behavior provides new perspectives on constraints in bird flight and might help to explain the evolution of nocturnal migration.

DOI: 10.1126/science.abe7291

Source: https://science.sciencemag.org/content/372/6542/646